Plasmonic Nanocavity Induced Coupling and Boost of Dark Excitons in Monolayer WSe2 at Room Temperature

Tsz Wing Lo, Xiaolin Chen, Zhedong Zhang, Qiang Zhang, Chi Wah Leung, Anatoly V. Zayats, Dangyuan Lei

Research output: Journal article publicationJournal articleAcademic researchpeer-review

28 Citations (Scopus)


Spin-forbidden excitons in monolayer transition metal dichalcogenides are optically inactive at room temperature. Probing and manipulating these dark excitons are essential for understanding exciton spin relaxation and valley coherence of these 2D materials. Here, we show that the coupling of dark excitons to a metal nanoparticle-on-mirror cavity leads to plasmon-induced resonant emission with the intensity comparable to that of the spin-allowed bright excitons. A three-state quantum model combined with full-wave electrodynamic calculations reveals that the radiative decay rate of the dark excitons can be enhanced by nearly 6 orders of magnitude through the Purcell effect, therefore compensating its intrinsic nature of weak radiation. Our nanocavity approach provides a useful paradigm for understanding the room-temperature dynamics of dark excitons, potentially paving the road for employing dark exciton in quantum computing and nanoscale optoelectronics.

Original languageEnglish
Pages (from-to)1915-1921
Number of pages7
JournalNano Letters
Issue number5
Publication statusPublished - 9 Mar 2022


  • plasmonic cavities
  • Purcell factor
  • spin forbidden dark exciton
  • transition metal dichalcogenides
  • two-dimensional materials

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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